Method of and apparatus for forced-air heating



June 12, 1928. 1,673,074

4 GT. HOUGHTBY METHOD OF AND APPARATUS FOR FORCED AIR HEATING F l Augi1927 2 ShetsShe 1 June 12, 1928.

(5. T. HOUGHTBY METHOD OF AND APPARATUS FOR FORCED AIR HEATING 2Sheets-Sheet Filed Aug. 22, 1927 Patented June 12, 1928.

UNITED STATES GEORGE TI TUS HOUGH'IBY, OF LONDON, ONTARIO, CANADA.

METHOD or AND ArrAnAT'U's Foal FORCED-AIR HEATING.

Application filed August 22, 1927. Serial No. 214,546.

In a warm air heating system, convection is the means by which heat istransferred from the heating surfaces of the furnace to the register andthe number of heat units delivered in a given space of time isdetermined by the volume and temperature of the air that issues from it.Tests have shown that the average air temperatures at the register rangefrom 120 to 220 F. depend ing upon the rate at which the fuel isconsumed and the initial temperature of the air entering the heatingzone of the furnace,

pound of air that passes into the room during the hour must contain 36B. t. u. available for producing the desired heating effeet and it willtherefore require 368 pounds of air hourly to equal the loss. If the airtemperature at the register is 120 F. every pound of air that passesinto the room during the hour will contain 12 B. t. u. available forproducing the desired heating effect and instead of 368 pounds of air itwill be necessary to supply 1100 pounds of air hourly to equalize theheat loss or three times as much air by weight must be supplied to theroom if the temperature at the register is 120 F. as would berequired-if the temperature is 220 In gravity warm air heating systems asingle current enters the heating zone of the furnace and expands orbecomes lighter in weight as its temperature rises, thereby producin anunbalanced condition on the warm and cold air sides and causing adisplacement or circulation limited largely by the capacity of theintake and discharge. To offset these limitations it is customary to usea centrifugal fan for increasing the velocity head of the current butheretofore the use of the fan has been confined to the acceleration ofthis single air current and the air temperature at the register has beenlimited to the B. t. u.'from the heated sur faces of the combustionzone.

My present invention relates to a forced air heating system in which anair current is established through each of two zones. One of these zonesis heated from the surfaces of the combustion chamber to a temperaturewhich may exceed 220 F. and contain over 36 B. t. u.s per pound of airat the register, and the other zone may be heated, by the wasteproducts' of combustion passing through the smoke pipe to a temperaturewhich may exceed 120 F. and contains at least 12 B. t. u.s per pound ofair at the register or this last mentioned zone may su ply a. current offresh or cold air. The ve ocity head of each current is mechanicallymaintained by a centrifugal fan the speed of which is regulated to therequired. capacity of the furnace. The fan comprises a rotor providedwith two sets of blades each operating to create an accelerated currentthrough its respective zone and with a diaphragm which effects theseparation of the two currents untilexpelled by the fan beyond therotational path of the blades, where they are mixed and combined into asinglecurrent.

In the construction shown in the drawings and hereinafter described. thefan blades of one set are hollow or tubular, their inner ends arebevelled or chisel shaped to form a central co noidal, recess around thehub, the bones of the blades are open atboth ends, and the inner ends ofthe bores communicate withthe recess. The other set con sists ofweb-shaped vanes extending radially from the hub and operating to drawthe air into the recess and expelit through the hollow or tubularblades. Flanges extend latorally from the upper edges of the sides ofeach blade and flanges of adjacent blades are riveted, welded orotherwise secured together to form a diaphragm which connects and bracesthe. blades and separates the air currents at one side of the rotor fromthe air currents at the other side. An annular plate or ringoverlies'and is secured to the top of the hollow blades and to the webshaped vanes for securing them together and ensuring their unitedrotation, and this annular plate or ring is formed with a centralorifice co-axial with the conoidal recess. At one side-0f the diaphragm,the vanes create a current in the conoidal recess and expel it throughthe'hollow blades and at the other sidethe blades create a current whichis separate from that in the recess until the two currents are expelledbeyond the rotational path of the rotor.

For an understanding of the invention part of the furnace on the line22, Fig. 1, v

reference is to beihad to the following description and to theaccompanying drawings, in which:

Fig. 1 is a sectional plan view of the furnace, r Fig. 2 is avertical'section otthe upper Fig. 3 is aplan view of the rotor partly insection on a larger scale than Figs. 1 and'2, r n

Fig. 4 is a vertical section on the line 4--1, Fig. 3,

Fig. 5 is a plan view of the fan hub,

Fig. 6 is a vertical section on the line 66, Fig. 5, I

Fig.7 is a perspective view of one of the fan blades,

Fig. 8 is a side elevation showing an alternative method of faninstallation, and

Fig. 9 is a vertical section of the smoke pipe and a heater or drumsurrounding it.

Like numerals of reference refer to like parts. throughout thespecification and draw-' from a zone exterior ofthe turnaceandineither'case is combined with the air from the other zone. In both ofthese Zones the movement of the air currents is accelerated by a fanwhich includes arotor compris ing a hub and two separated sets ofblades,

each of which creates a current independently of the other set. f I

The fan shown in; the drawings comprises 'a set of hollow or tubularblades 4 and ahub consisting of a "sleeve 1 provided with jfourweb-shaped arms 2 extending radially from it and a'lug 3 at the outerend of each arm. The bore 5 of each blade 4'is open at both ends for thecirculation of the air through the blade, and the inner end of eachblade is bevelled or chisel shaped. The blades are'assembled with thehubrafter the manner of the spokes of a wheel, as shown inFi'g. 3. andin this'assembly the bevelled or'chisel shaped ends of the bladesabut'around the central sleeve 1 and form a conoidal recess 8. 'Theinner end of the bore 5 of each blade communicates with the recess andthe web-shaped arms 2 extend'from the-sleeve across the which separatesthe air currents at one side of the rotor from the air currents at theother side. An annular plate or ring 6 overlies the blades 4 and issecured to them a and to the lugs 3 for connecting the blades to'lugs 3and this plate or ring is formed with a central aperture or orifice 7overlying and of corresponding area to the recess 8. At the lower edgeof each blade 4 is a curved or inclinedflange 9 extending radially fromthe sleeve part way to the periphcry of the rotor and laterally from thelower edge of the blade, for the purpose of efi'ectin'g an uplift of theair into the path of the blade during its revolution. The

. the two air currents to mixwhen expelled beyond the periphery of therotor.

The fan housing or casing 10 contains two chambers 12 and 1i and therotor revolves in the chamber 12. The chamber 14 is above the chamber 12and has a sloping bottom 15 formed with a central aperture 16 and adownturne'd flange 17 entered through the central aperture '7 in theplate or ring 6.

The chambenll i has an inlet 18 connected 1 by a pipe -18 with a drum orheater 18 surrounding the smoke pipe 18 The heater or drum may consistof two telescopic sections which can be contracted for decreasing, orextended for increasing, its heating capacity.

The drum is provided with a damper controlled air intake 18 which may beconnected with a cold air supply leading to the exterior of the buildingor toany other convenient location. The air circulates through thedamper controlled intake to the heater or drum and through the inlet 18to the chamber 14. Thi inlet'18 is provided with a balanced damper 19which automatically opens under the pressure of the inf'lowing airduring the operation of the tan and auto matically closes when the fanstops. An electric motor 20 is mounted'on the top of the housing orcasing 10 and is provided with a motor shaft 21 which extends into andis'connected with the fan hub. but any other type of drive may be used.The fan is shown in 1 and 2 to be located above the heating surfaces ofthe furnace butit may be installed between the furnace and the registersor in any other part of the system, shown ,in Fig. 8, and used to temperanddistribute the air or to supply a current of fresh air taken from theexterior of the building and mix it with the heated air. The blades 1 ofthe fan during its operation, create a forced circulation of air fromthe heating zone or free airspace between the heated surfaces of thecombustion chamber 30 and the casing 31 and expel it beyond therotational path'of the fan and the webshaped arms or vanes 2 create acurrent into i in CAI

, these two currents into a single current within the fan housing.

Having thus fully described my invention what I claim as new and desireto secure by Letters Patent is:

1. The hereindescribed method of forced air heating which consists ofsimultaneously creating an air current in each of two separated zones,heating the air in at least one of the zones, maintaining the separationof the currents during the heating stage, expelling them from theirrespective zones, and combining them when expelled.

2. The hereindescribed method of forced air heating which consists ofsimultaneously creating an air current in each of two separated heatingzones, heating the air in at least one of the zones, maintaining theseparation of the currents during the heating stage, increasing theirvelocity head, expelling them from their respective zones, and combiningthem when expelled.

3. In an apparatus for forced air heating, the combination of a furnacehaving two separate heating zones. a centrifugal fan for creatingacurrent through each of the two separate zones. said fan having a rotorcomprising a hub, a set of hollow blades open at both ends and shaped attheir inner ends to form a recess around the hub. a set of vanesextending radially from the hub into the recess, and a diaphragmseparating the air current at one side of the rotor from the air currentat the other side, the blades creating at one side of the diaphragm anair current through one of the Zones and expelling it from the fan, andthe vanes at the opposite side of the diaphragm creating an air currentthrough the other zone into the recess and expelling it through thehollow blades to combine with the air current expelled by the blades. I

4. In an apparatus for forced air heating, the combination of a furnacehaving two separate heating zones. a centrifugal fan for creating acurrent through each of the two separate zones, said fan having a rotorcomprising a hub, a set of hollow blades open at both ends and shaped attheir inner ends to form a recess around the hub. a set of vanesextending radially from the hub into the recess, and a diaphragmseparating the a r current at one one side of the rotor from the aircurrent at the other side, the blades creating at one side of thediaphragm an air current through one of the zones and expelling it fromthe fang'a-n-d the vanes at the opposite side of the diaphra rn creatingan air current through the ot'cr zone into the recess and expelling itthrough the hollow blades to combine with the air current expelled bythe blades, and deflectors for retarding the re.- 7

tation of the air currents and causing the velocity head to build up asthe rotor revolves.

5. In an apparatus for forced'air heating as claimed in claim 3, inwhich the rotor of the centrifugal fan is enclosed in a housingcontaining two chambers, in one of which the rotor revolves and is incommunication with one of said zones, and the other of which is abovethe first mentioned chamber and is provided with an inlet incommunication with the other zone and the recess.

6. In an apparatus for forced air'heating as claimed in claim 3 in whicheach blade is I provided with a radial flange extending laterally fromits lower edge for effecting the uplift of the air into the path of theblade during the rotation of the rotor.

7 In an apparatus for forced air heating, the combination of a furnacehaving two separate heating zones, a centrifugal fan for creating acurrent through each of the two separate zones, said fan having a rotorcomprising aset of blades for creating an air cur-,

rent at one side of the rotor through one of the zones and expelling itfrom the fan, and a set of vanes at the other side of the rotor forcreating an air current through the other zone and expelling it tocombine with the first mentioned current, and a diaphragm formaintaining the separation of the two currents until expelled.

8. In an apparatus for forced air heating, the combination of a furnacehaving two separate heating zones, a centrifugal fan for oreating acurrent through each of the two separate heating zones, said fancomprising a rotor having a set of hollow blades for creating, at oneside of the rotor, an air current through one of the zones and expellingit from the fan, and a set of vanes at the other side of the rotor forcreating an air current through the other zone and expelling it throughthe hollow blades to combine with the first-mentioned current.

9. In an apparatus for forced air heating, a

furnace having a free air space heated from the combustion zone. and adrum heated by the products of combust on, 1n combination with a fancomprising a rotor having two sets of blades separated by a diaphragm,one set of blades creating a current through said free air space, andthe other set of blades creating a current through the drum, each set ofblades increasing the velocity head of its respective current andexpelling it from the fan to combine with the other current, and thediagram maintaining the separation of the two currents until expelled bythe fan.

10. In an apparatus for forced air heating the combination of afurnacehaving two sepis heated in the other zone and expelled arate heatingzones and a centrifugal fan through'the hollow blades to combine vwith10 having a rotor comprising a set of hollow the first-mentionedcurrent.

blades for creating at one side of the rotor an Dated at the city ofLondon, in the county. air current Wl'llCll lS heated in one '01": theof Middles eX and Province'ot Ontario, Do-

zones and expelled by the blades from the minion of Canada, thethirteenth day o1 tan and a set of vanes for creatin gnt the August,1927.

, other side of the rotor an air current Which GEORGE TITUS HOUGrHTBY.

